1. Field of the Invention
The present invention relates to a record apparatus, a record method, and a program thereof that allow a record operation to be effectively performed when a record unit of data of a record medium in particular an optical disc is different from a management unit of data of a file system.
2. Description of the Related Art
In recent years, optical discs that allow a large amount of data to be recorded and reproduced using a laser beam having a short wavelength as a light source have come out. For example, a record capacity of 23 GB (Gigabytes) using a blue-purple laser that emits a laser beam having a wavelength of 405 nm as a light source and that has a single-side one-layer optical disc has been accomplished.
This optical disc has been proposed for a record medium for a video/audio device used in a broadcasting station. This optical disc is loaded into a video camera or a camera controller connected thereto. Video data corresponding to a picture photographed by a video camera is recorded to the loaded optical disc. In addition, sound associated with the picture is collected by a microphone. Audio data corresponding to the collected sound is recorded to the optical disc. The video data and the audio data are recorded for example as different files for each clip. A clip is a block of data for which a photographing operation is started until it is stopped.
United States Patent Application Unexamined Publication No. US2003/0215212 describes a device that records a low resolution sub video signal along with a high resolution main video signal to an optical disc.
A unit in which AV data are recoded and reproduced to and from an optical disc may be as large as 64 kB (kilobytes). On the other hand, as a file system for an optical disc, UDF (Universal Disk Format) has become common. The UDF manages data that are recorded and reproduced in a unit of 2 kB.
Next, a record process performed when a data size of a record/reproduction unit of a record medium is different from a data size of a management unit of a file system will be described. In this example, it is assumed that the record medium is an optical disc having a record/reproduction unit of 6 kB and the file system has a management unit of 2 kB.
When a file having a data size of for example 70 kB is written from the beginning of each record unit, 64 kB of 70 kB is written to the first record unit #1. The remaining 6 kB is written to the next record unit #2. This record process is accomplished by a function called a cache that temporarily stores data corresponding to the record/reproduction unit of the record medium to a buffer memory or the like.
When data of one record unit are stored in the buffer or when an unload command for an optical disc is issued from a drive, data for the cached record unit are read from the memory and written to the optical disc.
Now, it is assumed that the optical disc on which data of 70 kB have been written is unloaded from the drive, the disc is loaded into the drive, and then data are recorded on the disc. In this case, a write control called the read modify write using a cache is normally performed. Next, the read modify write will be described in brief.
Data are read from the record unit #2. The read data are cached to a buffer memory or the like. In this example, since data of 6 kB have been written to the record unit #2, the data of 6 kB are cached. The newly recorded data are preceded by the cached data. When the amount of cached data becomes 64 kB, the cached content is overwritten to the record unit #2 of the optical disc.
When the read modify write is used, even if the data size of the management unit of the file system is smaller than the data size of the record/reproduction unit of the record medium, data can be recorded and reproduced in the management unit of the file system.